Split Decision Leads to Progress for Nathan Eovaldi

Nathan Eovaldi started the season as the Yankees’ pet project, but, in the early going, there was very little progress to report…and that was before the right hander was rocked for eight first inning runs during a June outing in Miami. Thankfully, the Bronx Bombers didn’t get frustrated and cut bait on the former Marlin because, since that time, Eovaldi has turned his season around.

Turning Point: Nathan Eovaldi’s Performance Before and After June 16Note: On June 16, Eovaldi surrendered eight earned runs in 2/3 innings.
Source: baseball-reference.com

Eovaldi’s disastrous outing on June 16 seems like the obvious turning point in his season. However, a more seminal moment occurred two starts earlier, when, for the first time, the hard throwing righty began to use his split finger fastball. Before June 5, Eovaldi had only thrown 45 splitters, or less than 5% of his pitch total for the season, but, beginning with that outing, he began to trust it more. Since then, the split finger has consistently comprised about 20% to 30% of Eovaldi’s repertoire, and, more importantly, it has been very effective. According to fangraphs.com, Eovaldi’s splitter has been worth 9.7 runs above average, which makes it one of the better pitches in the game (only 38 individual pitches rate higher among qualified starters).

Eovaldi has increased the number of splitters thrown to both lefties and righties, but employed the pitch somewhat differently to each. To lefties, he has basically replaced the less reliable slider, which had a tendency to break into the hitting zone, with a splitter located more toward the outside corner. The tradeoff has been astounding. Before June 16, Eovaldi’s slider made up 23% of all pitches to lefties, who hit .378 against it. Since then, the split finger has become more prevalent, rising to 21% of all pitches against lefties. The meager .174 batting average that lefties have mustered against the pitch since June 16 argues in favor of the change in repertoire.

Since embracing the splitter, Eovaldi’s other pitches, particularly the fastball, have also been more effective against lefties, perhaps because another pitch is now in the back of their minds. As a result, Eovaldi’s overall performance against southpaws has improved dramatically. Since June 16, Eovaldi’s OPS against left handed batters has been cut in half, effectively turning opposing lefties from Barry Bonds into Omar Quintanilla. The end result is Eovaldi has eliminated a weakness that was easy for opposing managers to exploit.

Against righties, Eovaldi’s use of the splitter has come at the expense of his fastball, which seems appropriate considering the similar horizontal movement of the two pitches. He has also used the splitter down in the zone and on both sides of the plate against right handers, once again mimicking his employment of the fastball. As with lefties, the results have been very favorable.

Since June 16, righties are hitting only .184 against the splitter, which is actually a lot higher than before, but there’s an added bonus. Eovaldi’s success with the fastball has increased significantly as well. By adding a pitch that looks like the fastball in terms of horizontal movement, location and release point, Eovaldi has added a layer of deception that has worked to his benefit. The result has been a modest improvement on already solid performance against right handed batters.

Snapshot of Nathan Eovaldi’s Pitch Movement and Release Point, August 19, 2015Note: Blue dots are fastballs; orange triangles are splitters. Data from game on August 19, 2015 only.
Source:fangraphs.com

After frustrating other organizations with his unfulfilled potential, Eovaldi has provided the Yankees will reason for optimism, but, by no means, is his development complete. Lefties are still easily handling his 96 mph fastball, and righties have had renewed success against his slider. That gives Eovaldi, and pitching coach Larry Rothschild, plenty of room for improvement, but at least now they are building on a foundation of production, not promise.